The present invention relates, in general, to an electromotive furniture double drive and switch arrangement.
A furniture double drive has two drive motors arranged on the side of a housing in pot-shaped motor casings. The furniture double drive, called “double drive” in the following description for sake of simplicity, has two speed reduction gear trains which are respectively coupled to the drive motors. A spindle is securely connected to the output element of each speed reduction gear train. A spindle nut, which is secured against rotation, sits on the spindle and forms the output element of each power train of the double drive. For example, a furniture component connected to an output element is adjusted via the output element, which sits securely on the spindle nut.
As an alternative, the double drive is equipped with a drive motor and a speed reduction gear train. This speed reduction gear train is designed in such a way that a spindle, which is secured against rotation, is movable in its longitudinal direction. This spindle then forms the output element of the double drive. The two end faces of the spindle and the attached output elements can be in a drive connection with the components to be adjusted, depending on the movement direction of the spindle.
Another approach involves a double drive which includes two individual drives, wherein each electric motor, together with a speed reduction gear train and an output element, is arranged in a respective housing. The two housings are either directly connected to each other or connected to each other by at least one connection element which is arranged between the housings.
The end switch(es) are arranged in a so-called end switch rail having a U-shaped cross section. The middle leg of this end switch rail is provided with a row of holes so that the end switches can be placed at different positions in the end switch rails. The respective end switch controls hereby the motor by switching off the motor circuit as the end switch makes contact, when the output element reaches a middle position or an end position, for example. There are many drawbacks associated with this approach. Adjustment of the end switches requires opening of the housing in order to render the end switches accessible. In addition, as the positions of the end switches depend on the required adjustment path and the adjustment range of the furniture component to be adjusted, users of double drives perceive this type of end switch adjustment as inadequate since one cannot see how the end positions of the output elements of a furniture drive are to be adjusted.
It would therefore be desirable and advantageous to address these problems and to obviate other prior art shortcomings